The present invention relates to an apparatus used in verifying that the controls for a transit car, such as a subway car, are being sequenced properly by a master controller.
The master controller for a transit car allows a train operator to manually select the proper speed and direction of the car and to control the brakes and other functions. The master controller sends signals to a control package mounted under the car. Among the functions of the control package is to control the power to the car's motors for smooth acceleration and braking.
In the past, to test the operation of the control package, one device which has been employed is a portable sequence tester which simulates master controller signals for sequencing the control package through its various functions to insure proper operation. When using the portable sequence tester, a "shorting plug" with internal jumper wires is first removed from a relay panel contained in the control package. A control wiring harness for the portable sequence tester is then used to provide an interface between the tester and the control package, and all of the testing is done by the person operating the portable sequence tester under the car. During sequence testing, the portable sequence tester is set to a desired power state, simulating signals from the master controller to be sequentially transmitted to the control package. The operation of the control package is then observed.
Safety regulations now require that testing of the control package be carried out with an operator directly controlling the car's master controller from the cab of the transit car. These regulations effectively require two maintenance workers to carry out sequence testing of the control package: one person to operate the master controller in the cab of the car to issue master controller requests to the control package and a second person under the car to verify the proper operation of the control package.
The new testing procedures using two workers, as described above, is subject to error when using currently available testing equipment which requires connection of two temporary jumper wires into the control package to provide the proper control wiring paths needed to verify the proper operation of the control package from the cab request. This works satisfactorily until human error is introduced. For example, jumper wires are not always installed in the proper location or touch adjacent electrical termination points causing damage to a propulsion logic board for the control package.